Slice the eggplant longways. Place the sliced eggplant onto a tray or cookie sheet and generously sprinkle salt onto the eggplant slices. Let the eggplant sit and "sweat" for 25 minutes.
While the eggplant is set aside, preheat the oven to 400 degrees F, and start making the meat sauce.
Put the onion, garlic, and 1 Tbs of olive oil into a large pan and heat over medium heat for about 3 minutes, mixing every so often.
Add the ground turkey to the pan, and try to break it up into smaller pieces with a rubber spatula. Put 1/2 tsp salt, 1/2 tsp ground black pepper, 1/2 tsp oregano, 1 tsp of paprika, and 1/2 tsp of basil onto the meat, and mix it all together. Let the meat cook for 7-8 minutes, until browned.
Add the tomato paste to the meat, and mix. Let the mixture cook for another minute.
Then, add the strained tomatoes and water to the dish, and mix. Top the sauce with 1/2 tsp salt, 1/2 tsp ground black pepper, 1/2 tsp oregano, 1/2 tsp of basil, and 1/2 tsp paprika (you could add 1 tsp of paprika here, but make sure you taste the sauce to see if you want more smokiness or not). Mix and let the mixture cook for 5 minutes.
Then take paper towels and remove the liquid from the eggplant.
Put 2 cups of meat sauce into an 11x 9 inch baking dish. Then layer the eggplant across the top of the sauce. Cover the eggplant in 1.5 cups of the meat sauce, and spread it around with a spatula, then layer all of the slices of bell pepper onto the surface of the sauce. Cover the pepper with 1.5 cups of the meat sauce, spread it around with a spatula, and then layer the zucchini slices on top of the sauce. (You should have used up all of the meat sauce and veggies at this point)
If you are using dairy, sprinkle the top with mozzarella or parmesan ( or both).
Bake for 40 minutes, or until you can easily stick a knife into the casserole and the veggies are all soft.